1. Field of the Invention
The present invention relates generally to a hand tool, and more particularly to a ratchet wrench, which can provide larger power and can drive a pawl moving stably.
2. Description of the Related Art
FIG. 9 shows a conventional ratchet wrench 8, which comprises a handle 80 having a head portion 81 at an end thereof. The head portion 81 is provided with a through 811, a first chamber 812 and a second chamber 813. A driving device 82 having teeth 821 at a annular outer surface thereof is installed in the through hole 811 via a C-ring 88 such that the driving device is rotatable. A pawl 83 is received in the first chamber 812 meshed with the teeth 821 of the driving device 82. A switching device 84 is received in the second chamber 813, which has a recess 841 along a diameter orientation thereof in which installs a spring 85 and a bullet 86. The bullet 86 elastically pushes the pawl 83. A positioning member 87 is installed in a recess 814 on a sidewall of the second chamber 813 against the switching device 84.
The combination of the spring 85 and the bullet 86 generally has two functions, one of which is elastically pushing the pawl 83 to make it meshed with the teeth 821 of the driving device 82, the other one of which is moving the pawl 82 to right side or left side of the first chamber 812. The driving device 82 is turned with the handle 80 when the handle 80 is turned forwards, so that the driving device 82 can turn a nut or a bolt. But, when the handle 80 is turned reversibly, the driving device 82 will keep still.
FIG. 10 shows another conventional ratchet wrench 9, which is similar to aforesaid conventional ratchet wrench 8, except that an elongated piece element 96 is replaced with the bullet 86 of the ratchet wrench 8. The elongated piece element 96 works for same functions.
In practice, the driving device 82 will be driving to turn more or less when the handle 80 is turned reversibly. This trend of the driving device is requested to be less, otherwise, the wrench will unable to turn a loosed nut or bolt.
A considerable reason of aforesaid result is the strength of the spring. It is asked to as less as possible so that the bullet 86 (or the piece element 96) will has less affect of the pawl departing from the driving device when the handle is turned reversibly. But, a spring with smaller strength might cause the pawl cannot mesh with the driving device securely when the handle is turned forwards.
The primary objective of the present invention is to provide a ratchet wrench, which has less capacity of driving a driving device turning when the wrench is turned reversibly.
According to the objectives of the present invention, a ratchet wrench comprises a handle having a head portion at an end thereof, a through hole, a first chamber and a second chamber at the head portion, wherein the first chamber has opposite sides thereof communicated with the through hole and the second chamber respectively. A driving device has a polygonal hole at a center thereof and teeth at an outer side thereof whereby the driving device is installed in the through hole of the handle for free rotation. A pawl has teeth at a side thereof and a driven portion at an opposite side thereof, whereby the pawl is received in the first chamber and detachably meshes the teeth thereof with the teeth of the driving device. A switching device has an axle member and a turning member at an end of the axle member, wherein the axle member is received in the second chamber of the handle for free rotation and the turning member is left out of the handle. A supporting device, which is substantially a strip element, has two substantially parallel extending segments and a contacting segment with opposite ends thereof connected with distal ends of the extending segments, wherein proximal ends of the extending segments are movably connected with the axle member of the switching device and the contacting segment is received in the first chamber of the handle, and means for driving the contacting segment having at least a part thereof elastically against the pawl at the driven portion.